Acid-proof casting



Patented Oct. 24, 1922.

UNITED STATES PATIENT @FFHCZE.

HENRI TERRISSE AND MARCEL LEVY, OF GENEVA, SWITZLALND.

ACID-PROOF CASTING.

Ho Drawing.

ing iron and silicon may be obtained, and- I that such castings will beproof against mineral acids especially halogen acids, when said castingscontain about to 30 per cent of silicon. Such castings, however, cannotbe easily made on account of the brittle nature of the mineral whichwill easily disintegrate and crumble to pieces. It is also known thatferro-tungsten and ferro-vanadium castings will also become acid-proofif a high percentage of tungsten or vanadium is used, but these alloysdo not give very satisfactory acid-proofness; and furthermore all suchalloys of tungsten, vanadium or a mixture thereof are very difiicult tocast.

We have found that all these disadvantages can be overcome, and thateasily moulded castings which will have a very high resistance, eitherwhen cold or when warm, against halogen acids and other min-.

eral or organic acids can be obtained. To

these ends, in accordance with the present invention, we make castingsfrom mixtures of iron, silicon and a metal adapted to increase themechanical, and chemical resistance of the casting, such as, forexample, tungsten,

9 or, vanadium, or a mixture of. the four metals.

In forming such castings, we subject ferro-silicon to heat to melt thesame; and while in the molten state, we add thereto at least one metalto increase its mechanical and chemical resistance, such metal being,

for example, tungsten or vanadium.

These metals may be added either in a combined form, such asferro-tungsten or ferro-vanadium, or as the silicide of tungsten orsilicide of vanadium. I

In carrying out the process, iron and sili- Application filed July8,-1920. Serial No. 394,722.

the molten metal and a homogeneous, easily con are chosen so as to form'ferro-silicon with from 10 to 30 per cent of silicon, so as to obtain analloy having a melting point at about 1200 to 1300 C. 'A metal such asferro-tungsten or ferro-vanadium is then added thereto, so as to obtainan alloy containing from 2 to 20 per cent and more oftungsten orvanadium.

The castings thus produced will have great brightness and will nottarnish when exposed to the air and they will also have greatacid-proofness and can be easily.

moulded. In analyzing such alloys, it has been found that there willexist most probably some ternary combinations of iron, silicon andtungsten or of iron, silicon and vanadium, which combinations are verystable.

The ingredients may be used in about the following proportions:

186 E mampla-lOO kilograms of ferro-silicon having 20 per cent siliconare melted down, and 30 kilograms of ferro-tungsten havin 50 per centtungsten are added thereto. he tungsten is rapidly dissolved in runningmass will be obtained. If a rapid chilling is desired, the casting iscompleted by usin chills.

2nd acample.l00 kilograms of ferrosilicon having 15 per cent silicon aremelted down, and 28 kilograms of tungsten silicide having 19 per centsilicon are added thereto; the subsequent procedure being the same as inthe first example. Ferro-vanadium and silicide ofvanadium may be usedinstead of ferro-tungsten and silicide of tungsten.

We claim: I An acid proof casting which has great mechanical andchemical resistance made from an alloy containing iron, silicon, andtungsten, and which contains from ten to thirty per cent silicon andfrom two to twenty per cent of tungsten.

In testimony whereof we afiix our signatures in presence of twowitnesses.

' HENRI TERRISSE.

MARCEL LEVY. Witnesses: Dr. Ron. DE WURTEMBERG,

THEODORE I

